1,2,3,4,7,8-Hexahydro-6H-[1,4]diazepino[6,7,1-ij] quinoline derivatives as antipsychotic and antiobesity agents

ABSTRACT

Compounds of Formula I or a pharmaceutically acceptable salt thereof are provided:  
                 
 
where R 1  through R 7  are defined herein. The compounds of Formula I are 5HT2c agonists or partial agonists, and are useful for treating a variety of disorders.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 10/422,592filed on Apr. 24, 2003, which claims the benefit of U.S. ProvisionalApplication No. 60/376,153, filed Apr. 25, 2002, both of which arehereby entirely incorporated by reference.

BACKGROUND OF THE INVENTION

Schizophrenia affects approximately 5 million people. At present, themost widespread treatments for schizophrenia are the ‘atypical’antipsychotics, which combine dopamine (D₂) receptor antagonism withserotonin (5-HT_(2A)) receptor antagonism. Despite the reported advancesin efficacy and side-effect liability of atypical antipsychotics overtypical antipsychotics, these compounds do not adequately treat all ofthe symptoms of schizophrenia and are accompanied by problematic sideeffects including weight gain (Allison, D. B., et. al., Am. J.Psychiatry, 156: 1686-1696, 1999; Masand, P. S., Exp. Opin.Pharmacother. I: 377-389, 2000; Whitaker, R., Spectrum Life Sciences.Decision Resources. 2:1-9, 2000). Novel antipsychotics which areeffective in treating the mood disorders or the cognitive impairments inschizophrenia without producing weight gain would represent asignificant advance in the treatment of schizophrenia.

5-HT_(2C) agonists and partial agonists represent a novel therapeuticapproach toward the treatment of schizophrenia. Several lines ofevidence support a role for 5-HT_(2C) receptor agonism as a treatmentfor schizophrenia. Studies with 5-HT_(2C) antagonists suggest that thesecompounds increase synaptic levels of dopamine and may be effective inanimal models of Parkinson's disease (Di Matteo, V., et. al.,Neuropharmacology 37: 265-272, 1998; Fox, S. H., et. al., ExperimentalNeurology 151: 35-49, 1998). Since the positive symptoms ofschizophrenia are associated with increased levels of dopamine,compounds with actions opposite those of 5-HT_(2C) antagonists such as5-HT_(2C) agonists and partial agonists should reduce levels of synapticdopamine. Recent studies have demonstrated that 5-HT_(2C) agonistsdecrease levels of dopamine in the prefrontal cortex and nucleusaccumbens (Millan, M. J., et. al., Neuropharmacology 37: 953-955, 1998;Di Matteo, V., et. al., Neuropharmacology 38: 1195-1205, 1999; DiGiovanni, G., et. al., Synapse 35: 53-61, 2000), brain regions that arethought to mediate critical antipsychotic effects of drugs likeclozapine. In contrast, 5-HT_(2C) agonists do not decrease dopaminelevels in the striatum, the brain region most closely associated withextrapyramidal side effects. In addition, a recent study demonstratesthat 5-HT_(2C) agonists decrease firing in the ventral tegmental area(VTA), but not in substantia nigra. The differential effects of5-HT_(2C) agonists in the mesolimbic pathway relative to thenigrostriatal pathway suggests that 5-HT_(2C) agonists will have limbicselectivity and will be less likely to produce extrapyramidal sideeffects associated with typical antipsychotics.

Atypical antipsychotics bind with high affinity to 5-HT_(2C) receptorsand function as 5-HT_(2C) receptor antagonists or inverse agonists.Weight gain is a problematic side effect associated with atypicalantipsychotics such as clozapine and olanzapine and it has beensuggested that 5-HT_(2C) antagonism is responsible for the increasedweight gain. Conversely, stimulation of the 5-HT_(2C) receptor is knownto result in decreased food intake and body weight (Walsh et. al.,Psychopharmacology 124: 57-73, 1996; Cowen, P. J., et. al., HumanPsychopharmacology 10: 385-391, 1995; Rosenzweig-Lipson, S., et. al.,ASPET abstract, 2000). As a result, 5-HT_(2C) agonists and partialagonists will be less likely to produce the body weight increasesassociated with current atypical antipsychotics. Indeed, 5-HT_(2C)agonists and partial agonists are of great interest for the treatment ofobesity, a medical disorder characterized by an excess of body fat oradipose tissue and associated with such comorbidities as Type IIdiabetes, cardiovascular disease, hypertension, hyperlipidemia, stroke,osteoarthritis, sleep apnea, gall bladder disease, gout, some cancers,some infertility, and early mortality.

SUMMARY OF THE INVENTION

In one embodiment, the present invention provides compounds of Formula I

where:

-   R¹ is hydrogen or alkyl of 1 to 6 carbon atoms;-   R² and R³ are each, independently, hydrogen, hydroxy, alkyl of 1-6    carbon atoms, alkoxy of 1-6 carbon atoms, halogen, carboxamido,    carboalkoxy of two to six carbon atoms, perfluoroalkyl of 1-6 carbon    atoms, cyano, alkanesulfonamido of 1-6 carbon atoms, alkanesulfonyl    of 1-6 carbon atoms, alkanamido of 1-6 carbon atoms, amino,    alkylamino of 1-6 carbon atoms, dialkylamino of 1-6 carbon atoms per    alkyl moiety, perfluoroalkoxy of 1-6 carbon atoms, alkanoyloxy of 2    to 6 carbon atoms, alkanoyl of 2 to 6 carbon atoms, aroyl of 6 to 8    carbon atoms, aryl of 5 to 7 carbon atoms, a C₆ to C₁₃ alkylaryl    group having 5 to 7 carbon atoms in the aryl moiety, a 5 to 7    membered heteroaryl group, or a 6 to 13 membered alkylheteroaryl    group having 5 to 7 members in the heteroaryl moiety, wherein any R²    or R³ substituent having an aryl or heteroaryl moiety may optionally    be substituted on the aryl or heteroaryl moiety with 1 to 3    substituents independently selected from a halogen atom, a C₁-C₆    alkyl group, or a C₁-C₆ alkoxy group;-   R⁴ and R⁵ are, independently, hydrogen or alkyl of 1 to 6 carbon    atoms, or R⁴ and R⁵, taken together with the carbons to which they    are attached, form a cyclic moiety selected from a cycloalkane of 4    to 8 carbon atoms, cycloalkene of 4 to 8 carbon atoms, bridged    bicyclic alkane of 5 to 10 carbon atoms, bridged bicyclic alkene of    5 to 10 carbon atoms, pyran or thiopyran in which the sulfur atom is    optionally oxidized to the sulfoxide or sulfone, wherein the cyclic    moiety formed by R⁴ and R⁵ may optionally be substituted with 1 to 3    substituents independently selected from a halogen atom, a C₁-C₆    alkyl group, or a C₁-C₆ alkoxy group;-   R⁶ and R⁷ are each, independently, hydrogen or alkyl of 1 to 6    carbon atoms; and-   n is 1 or 2; or a pharmaceutically acceptable salt thereof.

In another embodiment of the present invention, a method of treating amammal suffering from a condition selected from schizophrenia,schizophreniform disorder, schizoaffective disorder, delusionaldisorder, substance-induced psychotic disorder, L-DOPA-inducedpsychosis, psychosis associated with Alzheimer's dementia, psychosisassociated with Parkinson's disease, psychosis associated with Lewy bodydisease, dementia, memory deficit, intellectual deficit associated withAlzheimer's disease, bipolar disorders, depressive disorders, moodepisodes, anxiety disorders, adjustment disorders, eating disorders,epilepsy, sleep disorders, migraines, sexual dysfunction,gastrointestinal disorders, obesity, or a central nervous systemdeficiency associated with trauma, stroke, or spinal cord injury isprovided that includes administering to the mammal at least one compoundof Formula I or a pharmaceutically acceptable salt thereof.

In yet another embodiment of the present invention, a pharmaceuticalcomposition is provided that contains at least one compound of Formula Iand at least one pharmaceutically acceptable carrier or excipient.

DETAILED DESCRIPTION OF INVENTION

This invention provides compounds of Formula I

where

-   R¹ is hydrogen or alkyl of 1 to 6 carbon atoms;-   R² and R³ are each, independently, hydrogen, hydroxy, alkyl of 1-6    carbon atoms, alkoxy of 1-6 carbon atoms, halogen, carboxamido,    carboalkoxy of two to six carbon atoms, perfluoroalkyl of 1-6 carbon    atoms, cyano, alkanesulfonamido of 1-6 carbon atoms, alkanesulfonyl    of 1-6 carbon atoms, alkanamido of 1-6 carbon atoms, amino,    alkylamino of 1-6 carbon atoms, dialkylamino of 1-6 carbon atoms per    alkyl moiety, perfluoroalkoxy of 1-6 carbon atoms, alkanoyloxy of 2    to 6 carbon atoms, alkanoyl of 2 to 6 carbon atoms, aroyl of 6 to 8    carbon atoms, aryl of 5 to 7 carbon atoms, a C₆ to C₁₃ alkylaryl    group having 5 to 7 carbon atoms in the aryl moiety, a 5 to 7    membered heteroaryl group, or a 6 to 13 membered alkylheteroaryl    group having 5 to 7 members in the heteroaryl moiety, wherein any R²    or R³ substituent having an aryl or heteroaryl moiety may optionally    be substituted on the aryl or heteroaryl moiety with 1 to 3    substituents independently selected from a halogen atom, a C₁-C₆    alkyl group, or a C₁-C₆ alkoxy group;-   R⁴ and R⁵ are, independently, hydrogen or alkyl of 1 to 6 carbon    atoms, or R⁴ and R⁵, taken together with the carbons to which they    are attached, form a cyclic moiety selected from a cycloalkane of 4    to 8 carbon atoms, cycloalkene of 4 to 8 carbon atoms, bridged    bicyclic alkane of 5 to 10 carbon atoms, bridged bicyclic alkene of    5 to 10 carbon atoms, pyran or thiopyran in which the sulfur atom is    optionally oxidized to the sulfoxide or sulfone, wherein the cyclic    moiety formed by R⁴ and R⁵ may optionally be substituted with 1 to 3    substituents independently selected from a halogen atom, a C₁-C₆    alkyl group, or a C₁-C₆ alkoxy group;-   R⁶ and R⁷ are each, independently, hydrogen or alkyl of 1 to 6    carbon atoms; and-   n is 1 or 2;-   and pharmaceutically acceptable salts thereof.

In some preferred embodiments of the invention R² is hydrogen, halogen,cyano, perfluoroalkyl of 1 to 3 carbon atoms, alkyl of 1 to 6 carbonatoms, alkoxy of 1 to 6 carbon atoms, alkanoyl of 2 to 6 carbon atoms,or alkanesulfonyl of 1 to 6 carbon atoms or aryl of 5 to 7 carbon atoms.More preferably, R² is hydrogen, halogen, cyano, alkoxy of 1 to 3 carbonatoms, phenyl or trifluoromethyl.

In other preferred embodiments of the invention R³ is hydrogen, halogen,cyano, perfluoroalkyl of 1 to 3 carbon atoms, alkyl of 1 to 6 carbonatoms, alkoxy of 1 to 6 carbon atoms, alkanoyl of 2 to 6 carbon atoms,or alkanesulfonyl of 1 to 6 carbon atoms or aryl of 5 to 7 carbon atoms.More preferably, R³ is hydrogen, halogen, cyano, alkoxy of 1 to 3 carbonatoms, phenyl or trifluoromethyl.

R⁴ and R⁵ are preferably taken together, along with the carbon atoms towhich they are attached, to form a cycloalkane or cycloalkene moiety of5 to 8 carbon atoms, where one or more of the carbon atoms areoptionally substituted by alkyl of 1 to 4 carbon atoms, and morepreferably a cycloalkane moiety of 5 to 7 carbon atoms.

R¹, R⁶ and R⁷ are preferably hydrogen.

n is preferably 1.

In still other preferred embodiments of the invention, R² and R³ areindependently selected from hydrogen, halo, trifluoromethyl, phenyl oralkoxy of 1 to 3 carbon atoms, R¹, R⁶ and R⁷ are each hydrogen, n is 1,and R⁴ and R⁵, taken together with the carbon atoms to which they areattached, form cyclopentane, cyclohexane or cycloheptane.

The compounds of this invention contain asymmetric carbon atoms and thusgive rise to optical isomers and diastereoisomers. While shown withoutrespect to stereochemistry in Formula I, the present invention includessuch optical isomers and diastereoisomers; as well as the racemic andresolved, enantiomerically pure R and S stereoisomers; as well as othermixtures of the R and S stereoisomers and pharmaceutically acceptablesalts thereof.

Where an enantiomer is preferred, it may, in some embodiments beprovided substantially free of the corresponding enantiomer. Thus, anenantiomer substantially free of the corresponding enantiomer refers toa compound which is isolated or separated via separation techniques orprepared free of the corresponding enantiomer. “Substantially free,” asused herein, means that the compound is made up of a significantlygreater proportion of one enantiomer. In preferred embodiments thecompound is made up of at least about 90% by weight of a preferredenantiomer. In other embodiments of the invention, the compound is madeup of at least about 99% by weight of a preferred enantiomer. Preferredenantiomers may be isolated from racemic mixtures by any method known tothose skilled in the art, including high performance liquidchromatography (HPLC) and the formation and crystallization of chiralsalts or prepared by methods described herein. See, for example,Jacques, et al., Enantiomers, Racemates and Resolutions (WileyInterscience, New York, 1981); Wilen, S. H., et al., Tetrahedron 33:2725(1977); Eliel, E. L. Stereochemistry of Carbon Compounds (McGraw-Hill,N.Y., 1962); Wilen, S. H. Tables of Resolving Agents and OpticalResolutions p. 268 (E. L. Eliel, Ed., Univ. of Notre Dame Press, NotreDame, Ind. 1972).

Alkyl, as used herein, refers to an aliphatic hydrocarbon chain andincludes, but is not limited to, straight and branched chains such asmethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,t-butyl, n-pentyl, isopentyl, neo-pentyl, n-hexyl, and isohexyl. Loweralkyl refers to alkyl having 1 to 3 carbon atoms.

Alkanamido, as used herein, refers to the group R—C(═O)—NH— where R isan alkyl group of 1 to 5 carbon atoms.

Alkanoyl, as used herein, refers to the group R—C(═O)— where R is analkyl group of 1 to 5 carbon atoms.

Alkanoyloxy, as used herein, refers to the group R—C(═O)—O— where R isan alkyl group of 1 to 5 carbon atoms.

Alkanesulfonamido, as used herein, refers to the group R—S(O)₂—NH— whereR is an alkyl group of 1 to 6 carbon atoms.

Alkanesulfonyl, as used herein, refers to the group R—S(O)₂— where R isan alkyl group of 1 to 6 carbon atoms.

Alkoxy, as used herein, refers to the group R—O— where R is an alkylgroup of 1 to 6 carbon atoms.

Aryl, as used herein, refers to an aromatic 5- to 7-memberedmonocarbocyclic ring such as phenyl. Heteroaryl means an aromatic 5- to7-membered carbon containing monocyclic ring having one to twoheteroatoms which independently may be nitrogen, oxygen or sulfur.Groups containing aryl or heteroaryl moieties may optionally besubstituted as defined herein or unsubstituted.

Aroyl, as used herein, refers to the group Ar—C(═O)— where Ar is aryl asdefined above. For example, a C₆ to C₈ aroyl moiety refers to the groupAr—C(═O)— where Ar is an aromatic 5 to 7 membered carbocylic ring.

Alkylaryl, as used herein refers to the group —R—Ar where Ar is aryl asdefined above and R is an alkyl moiety having 1 to 6, preferably 1 to 4,and more preferably 1 to 3 carbon atoms. Examples of alkylaryl groupsinclude benzyl, phenethyl, 3-phenylpropyl, and 4-phenyl butyl.Alkylheteroaryl, as used herein, refers to the group —R-hetAr wherehetAr is heteroaryl as defined above and R is an alkyl moiety having 1to 6, preferably 1 to 4, and more preferably 1 to 3 carbon atoms.

Carboxamido, as used herein, refers to the group NH₂—C(═O)—.

Carboalkoxy as used herein refers to the group R—O—C(═O) where R is analkyl group of 1 to 5 carbon atoms.

Halogen (or halo) as used herein refers to chlorine, bromine, fluorineand iodine.

Pharmaceutically acceptable salts, including mono- and bi-salts, arethose derived from such organic and inorganic acids such as, but notlimited to acetic, lactic, citric, cinnamic, tartaric, succinic,fumaric, maleic, malonic, mandelic, malic, oxalic, propionic,hydrochloric, hydrobromic, phosphoric, nitric, sulfuric, glycolic,pyruvic, methanesulfonic, ethanesulfonic, toluenesulfonic, salicylic,benzoic, and similarly known acceptable acids.

Specific examples of compounds of Formula I include:

-   1,2,3,4,8,8a,9,11,11,11a-decahydro-cyclopenta[b][1,4]diazepino[6,7,1-ij]quinoline;-   1,2,3,4,8a,9,10,11,12,12a,-decahydro-8H-[1,4]diazepino[6,7,1-de]acridine;

and pharmaceutically acceptable salts thereof.

Specific examples also include substantially enantiomerically purecompounds of the foregoing including:

-   cis-1,2,3,4,8,8a,9,10,11,11a-decahydro-cyclopenta[b][1,4]diazepino[6,7,1-ij]quinoline;-   trans-1,2,3,4,8,8a,9,10,11,11a-decahydro-cyclopenta[b][1,4]diazepino[6,7,1-ij]quinoline;-   cis-1,2,3,4,8a,9,10,11,12,12a,-decahydro-8H-[1,4]diazepino[6,7,1-de]acridine;-   trans-1,2,3,4,8a,9,10,11,12,12a,-decahydro-8H-[1,4]diazepino[6,7,1-de]acridine;

and pharmaceutically acceptable salts thereof.

The compounds of this invention can be prepared according to thefollowing schemes from commercially available starting materials orstarting materials which can be prepared using literature procedures.Variables used are as defined for Formula I, unless otherwise noted.

In Scheme I, two different methods are shown for the preparation of theintermediate VI. In the top reaction, a substituted benzoisoxazole canbe reacted with the enamino derivative of a ketone in the presence of apremixed suspension of zinc powder and a Lewis acid such as titaniumtetrachloride in an organic solvent such as THF. The resultingsubstituted quinolines V can be subjected to catalytic hydrogenolysis inthe presence of a catalyst such as platinum oxide in an organic solventsuch as methanol to give intermediate VI. An alternative method for thesynthesis of VI is shown in the bottom equation of Scheme I. Treatmentof anthranilic acids with thionyl chloride in a solvent such as benzeneunder refluxing conditions followed by the addition of a ketone yieldsintermediates IV. These can then be reduced by lithium aluminum hydrideor sodium borohydride under acidic conditions to yield VI.

Scheme II exemplifies the conversion of VI to the final products.Intermediate VI can be alkylated, for instance with 2-chloroethyl amineunder phase transfer conditions to yield VII. Alternatively, the sidechain on VII can be installed via a two step procedure of alkylationwith 2-chloroacetamide followed by reduction. Another alternative forforming VII from VI is a two step procedure where first a —CH₂—CN groupis installed on the nitrogen of VI by the use of bromoacetonitrile inthe presence of tetrabutylammonium iodide, potassium carbonate and asolvent such as THF, and then second, the cyano group is reduced bycatalytic hydrogenation using for example rhodium on alumina in thepresence of ethanol and ammonium hydroxide. VII is then subject to apictet-spengler cyclization conditions with formaldehyde and a proticacid such as trifluoroacetic acid to yield VII.

VII can be resolved subsequently into its pure enantiomers by a chiralresolution to give compounds 1× and X. Alternatively, VII can bederivatised appropriately to give intermediate Xi, which can beseparated by chiral chromatography and then subject to cleavage to give1× and X. Compounds 1× and X can then be derivatised, for example, byalkylation, to give compounds XII and XII which are also products ofthis invention.

Scheme III exemplifies an alternative reaction scheme for producingcompounds of Formula I, where n is 2.

In Scheme III, 2-nitro-3-vinyl benzaldehyde is treated with a reducingagent such as tin dichloride in the presence of an acid such as conc.HCl to give 7-vinyl benzisoxazole XIV. Treatment of XIV with the enaminoderivative of a ketone XV in the presence of a premixed suspension ofzinc powder and a Lewis acid such as titanium tetrachloride in anorganic solvent such as THF yields a quinoline compound XVI. Standardhydroboration/oxidation of the alkene followed by protection of theresulting alcohol as acetate yields XVII. Compound XVII is subjected toreduction by Ni—Al alloy in an organic solvent such as methanol in thepresence of a strong base such as Aqueous KOH. The resultingtetrahydroquinoline compound XVIII can be alkylated under a variety ofconditions to install the side-chain. One such condition involvesalkylation with bromoacetonitrile and tetrabutylammonium iodide in thepresence of a base such as potassium carbonate in an organic solventsuch as THF to give the intermediate XIX. The acetate group of XIX canthen be deprotected with a base such as potassium carbonate in anorganic solvent such as methanol. The resulting alcohol is then subjectto oxidation with an agent such as PDC to give the aldehyde XX.Hydrogenation of the nitrile moiety in XX with rhodium on alumina in thepresence of hydrogen under pressure followed by ring closure to thealdehyde and subsequent reduction yields XXI which is a compound ofFormula I where n is 2.

The compounds of this invention are agonists and partial agonists at the2c subtype of brain serotonin receptors and are thus of interest for thetreatment of mental disorders, including psychotic disorders such asschizophrenia including paranoid type, disorganized type, catatonictype, and undifferentiated type, schizophreniform disorder,schizoaffective disorder, delusional disorder, substance-inducedpsychotic disorder, and psychotic disorder not otherwise specified;L-DOPA-induced psychosis; psychosis associated with Alzheimer'sdementia; psychosis associated with Parkinson's disease; psychosisassociated with Lewy body disease; bipolar disorders such as bipolar Idisorder, bipolar II disorder, and cyclothymic disorder; depressivedisorders such as major depressive disorder, dysthymic disorder,substance-induced mood disorder, and depressive disorder not otherwisespecified; mood episodes such as major depressive episode, manicepisode, mixed episode, and hypomanic episode; anxiety disorders such aspanic attack, agoraphobia, panic disorder, specific phobia, socialphobia, obsessive compulsive disorder, posttraumatic stress disorder,acute stress disorder, generalized anxiety disorder, separation anxietydisorder, substance-induced anxiety disorder, and anxiety disorder nototherwise specified; adjustment disorders such as adjustment disorderwith anxiety and/or depressed mood; intellectual deficit disorders suchas dementia, Alzheimer's disease, and memory deficit; eating disorders(e.g., hyperphagia, bulimia or anorexia nervosa) and combinations ofthese mental disorders that may be present in a mammal. For example,mood disorders such as depressive disorders or bipolar disorders oftenaccompany psychotic disorders such as schizophrenia. A more completedescription of the aforementioned mental disorders can be found in theDiagnostic and Statistical Manual of Mental Disorders, 4^(th) edition,Washington, D.C., American Psychiatric Association (1994).

The compounds of the present invention are also of interest for thetreatment of epilepsy; migraines; sexual dysfunction; sleep disorders;gastrointestinal disorders, such as malfunction of gastrointestinalmotility; and obesity, with its consequent comorbidities including TypeII diabetes, cardiovascular disease, hypertension, hyperlipidemia,stroke, osteoarthritis, sleep apnea, gall bladder disease, gout, somecancers, some infertility, and early mortality. The compounds of thepresent invention can also be used to treat central nervous systemdeficiencies associated, for example, with trauma, stroke, and spinalcord injuries. The compounds of the present invention can therefore beused to improve or inhibit further degradation of central nervous systemactivity during or following the malady or trauma in question. Includedin these improvements are maintenance or improvement in motor andmotility skills, control, coordination and strength.

The ability of the compounds of this invention to act as 5HT_(2C)agonists and partial agonists was established using several standardpharmacological test procedures; the procedures used and resultsobtained are provided below. In the test procedures, 5-HT stands for5-hydroxytryptamine, mCPP stands for meta-chlorophenylpiperazine, andDOI stands for 1-(2,5-dimethoxy-4-iodophenyl)isopropylamine.

5HT_(2c) Receptor Binding Test Procedures

To evaluate high affinity for the 5HT_(2C) receptor, a CHO (ChineseHamster Ovary) cell line transfected with the cDNA expressing the human5-hydroxytryptamine_(2C) (h5HT_(2C)) receptor was maintained in DMEM(Dulbecco's Modified Eagle Media) supplied with fetal calf serum,glutamine, and the markers: guaninephosphoribosyl transferase (GTP) andhypoxanthinethymidine (HT). The cells were allowed to grow to confluencein large culture dishes with intermediate changes of media andsplitting. Upon reaching confluence, the cells were harvested byscraping. The harvested cells were suspended in half volume of freshphysiological phosphate buffered saline (PBS) solution and centrifugedat low speed (900×g). This operation was repeated once more. Thecollected cells were then homogenized with a polytron at setting #7 for15 sec in ten volumes of 50 mM Tris.HCl, pH 7.4 and 0.5 mM EDTA. Thehomogenate was centrifuged at 900×g for 15 min to remove nuclearparticles and other cell debris. The pellet was discarded and thesupernatant fluid recentrifuged at 40,000×g for 30 min. The resultingpellet was resuspended in a small volume of Tris.HCl buffer and thetissue protein content was determined in aliquots of 10-25 microliter(μl) volumes. Bovine Serum Albumin (BSA) was used as the standard in theprotein determination by the method of (Lowry et al, J. Biol. Chem.,193: 265, 1951). The volume of the suspended cell membranes was adjustedwith 50 mM Tris.HCl buffer containing: 0.1% ascorbic acid, 10 mMpargyline and 4 mM CaCl₂ to give a tissue protein concentration of 1-2mg per ml of suspension. The preparation membrane suspension (many timesconcentrated) was aliquoted in 1 ml volumes and stored at −70 C untilused in subsequent binding experiments.

Binding measurements were performed in a 96 well microtiter plateformat, in a total volume of 200 μl. To each well was added: 60 μl ofincubation buffer made in 50 mM Tris.HCl buffer, pH 7.4 and containing 4mM CaCl₂; 20 μl of [¹²⁵I] DOI (S.A., 2200 Ci/mmol, NEN Life Science).

The dissociation constant, KD of [¹²⁵I] DOI at the human serotonin5HT_(2C) receptor was 0.4 nM by saturation binding with increasingconcentrations of [¹²⁵I] DOI. The reaction was initiated by the finaladdition of 100.0 μl of tissue suspension containing 50 μg of receptorprotein. Nonspecific binding is measured in the presence of 1 μMunlabeled DOI added in 20.0 μl volume. Test compounds were added in 20.0ml. The mixture was incubated at room temperature for 60 min. Theincubation was stopped by rapid filtration. The bound ligand-receptorcomplex was filtered off on a 96 well unifilter with a Packard®Filtermate 196 Harvester. The bound complex caught on the filter diskwas dried in a vacuum oven heated to 60° C. and the radioactivitymeasured by liquid scintillation with 40 μl Microscint-20 scintillant ina Packard TopCount® equipped with six (6) photomultiplier detectors.

Specific binding is defined as the total radioactivity bound less theamount bound in the presence of 1 μM unlabeled DOI. Binding in thepresence of varying concentrations of test drugs is expressed as percentof specific binding in the absence of drug. These results are thenplotted as log % bound vs log concentration of test drug. Non linearregression analysis of data points yields both the IC50 and the Kivalues of test compounds with 95% confidence limits. Alternatively, alinear regression line of decline of data points is plotted, from whichthe IC50 value can be read off the curve and the Ki value determined bysolving the following equation: ${Ki} = \frac{IC50}{1 + {L/{KD}}}$where L is the concentration of the radioactive ligand used and the KDis the dissociation constant of the ligand for the receptor, bothexpressed in nM.

The following K_(i)'s (95% confidence interval) are provided for variousreference compounds: Ritanserin 2.0 (1.3-3.1) nM Ketanserin 94.8(70.7-127.0) nM Mianserin 2.7 (1.9-3.8) nM Clozapine 23.2 (16.0-34.0) nMMethiothepin 4.6 (4.0-6.0) nM Methysergide 6.3 (4.6-8.6) nM Loxapine33.0 (24.0-47.0) nM mCPP 6.5 (4.8-9.0) nM DOI 6.2 (4.9-8.0) nMCalcium Mobilization in Response to 5-HT_(2C) Receptor Agonists

CHO cells stably expressing the human 5-HT_(2C) receptor were culturedin Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetalbovine serum and non-essential amino acids. Cells were plated at adensity of 40K cells/well in 96-well clear-bottom black-wall plates 24hr prior to the evaluation of 5HT_(2C) receptor stimulated calciummobilization. For calcium studies cells were loaded with the calciumindicator dye Fluo-3-AM in Hank's buffered saline (HBS) for 60 minutesat 37° C. Cells were washed with HBS at room temperature and transferredto the fluorometric imaging plate reader (FLIPR, Molecular Devices,Sunnyvale, Calif.) for acquisition of calcium images. Excitation at 488nm was achieved with an Argon ion laser and a 510-560 nm emission filterwas used. Fluorescence images and relative intensities were captured at1 second intervals and cells were stimulated by addition of agonistafter 10 baseline measurements using the internal fluidics module of theFLIPR. An increase in fluorescence counts corresponds to an increase inintracellular calcium.

For the evaluation of agonist pharmacology the calcium changes inresponse to different concentrations of agonist were determined using amaximum minus minimum calculation of the raw fluorescence count data.Calcium changes were then expressed as a percentage of the responseobserved with a maximally effective concentration of 5-HT and EC50values were estimated by non-linear regression analysis of thelog-concentration % maximum 5-HT response curves using the 4-parameterlogistic function.

The following EC₅₀'s and IC₅₀'s are provided for various referencecompounds: 5-HT EC50 0.5 nM DOI EC50 0.5 nM mCPP EC50 5.4 nM

The results of the standard experimental test procedures described inthe preceding paragraphs were as follows: 5-HT_(2C) Affinity 5-HT_(2C)Function (DOI/Agonist EC₅₀ Emax (%) Compound binding) KI (nM) (nM)(5-HT, 100%) Example 1, cis isomer 118 Example 1, trans isomer 71Example 2, cis isomer 511 Example 2, trans isomer 513

The compounds of this invention thus have affinity for and agonist orpartial agonist activity at brain serotonin receptors. They aretherefore of interest for the treatment of such CNS disorders, includingpsychotic disorders such as schizophrenia including paranoid type,disorganized type, catatonic type, and undifferentiated type,schizophreniform disorder, schizoaffective disorder, delusionaldisorder, substance-induced psychotic disorder, and psychotic disordernot otherwise specified; L-DOPA-induced psychosis; psychosis associatedwith Alzheimer's dementia; psychosis associated with Parkinson'sdisease; psychosis associated with Lewy body disease; bipolar disorderssuch as bipolar I disorder, bipolar II disorder, and cyclothymicdisorder; depressive disorders such as major depressive disorder,dysthymic disorder, substance-induced mood disorder, and depressivedisorder not otherwise specified; mood episodes such as major depressiveepisode, manic episode, mixed episode, and hypomanic episode; anxietydisorders such as panic attack, agoraphobia, panic disorder, specificphobia, social phobia, obsessive compulsive disorder, posttraumaticstress disorder, acute stress disorder, generalized anxiety disorder,separation anxiety disorder, substance-induced anxiety disorder, andanxiety disorder not otherwise specified; adjustment disorders such asadjustment disorder with anxiety and/or depressed mood; intellectualdeficit disorders such as dementia, Alzheimer's disease, and memorydeficit; eating disorders (e.g., hyperphagia, bulimia or anorexianervosa) and combinations of these mental disorders that may be presentin a mammal. For example, mood disorders or episodes, such as depressivedisorders or episodes often accompany psychotic disorders such asschizophrenia. A more complete description of the aforementioned mentaldisorders can be found in the Diagnostic and Statistical Manual ofMental Disorders, 4^(th) edition, Washington, D.C., American PsychiatricAssociation (1994).

The compounds of the present invention are also of interest for thetreatment of epilepsy; migraines; sexual dysfunction; sleep disorders;gastrointestinal disorders, such as malfunction of gastrointestinalmotility; and obesity, with its consequent comorbidities including TypeII diabetes, cardiovascular disease, hypertension, hyperlipidemia,stroke, osteoarthritis, sleep apnea, gall bladder disease, gout, somecancers, some infertility, and early mortality. The compounds of thepresent invention can also be used to treat central nervous systemdeficiencies associated, for example, with trauma, stroke, spinal cordinjuries. The compounds of the present invention can therefore be usedto improve or inhibit further degradation of central nervous systemactivity during or following the malady or trauma in question. Includedin these improvements are maintenance or improvement in motor andmotility skills, control, coordination and strength.

Thus the present invention provides methods of treating each of themaladies listed above in a mammal, preferably in a human, the methodscomprising providing a therapeutically effective amount of a compound ofthis invention to the mammal in need thereof. By “treating”, as usedherein, it is meant partially or completely alleviating, inhibiting,preventing, ameliorating and/or relieving the disorder. For example,“treating” as used herein includes partially or completely alleviating,inhibiting or relieving the condition in question. “Mammals” as usedherein refers to warm blooded vertebrate animals, such as humans.“Provide”, as used herein, means either directly administering acompound or composition of the present invention, or administering aprodrug derivative or analog which will form an equivalent amount of theactive compound or substance within the body.

Also encompassed by the present invention are pharmaceuticalcompositions for treating or controlling disease states or conditions ofthe central nervous system comprising at least one compound of FormulaI, mixtures thereof, and or pharmaceutical salts thereof, and apharmaceutically acceptable carrier therefore. Such compositions areprepared in accordance with acceptable pharmaceutical procedures, suchas described in Remingtons Pharmaceutical Sciences, 17th edition, ed.Alfonoso R. Gennaro, Mack Publishing Company, Easton, Pa. (1985).Pharmaceutically acceptable carriers are those that are compatible withthe other ingredients in the formulation and biologically acceptable.

The compounds of this invention may be administered orally orparenterally, neat or in combination with conventional pharmaceuticalcarriers, the proportion of which is determined by the solubility andchemical nature of the compound, chosen route of administration andstandard pharmacological practice. The pharamceutical carrier may besolid or liquid.

Applicable solid carriers can include one or more substances which mayalso act as flavoring agents, lubricants, solubilizers, suspendingagents, fillers, glidants, compression aids, binders ortablet-disintegrating agents or an encapsulating material. In powders,the carrier is a finely divided solid which is in admixture with thefinely divided active ingredient. In tablets, the active ingredient ismixed with a carrier having the necessary compression properties insuitable proportions and compacted in the shape and size desired. Thepowders and tablets preferably contain up to 99% of the activeingredient. Suitable solid carriers include, for example, calciumphosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch,gelatin, cellulose, methyl cellulose, sodium carboxymethyl cellulose,polyvinylpyrrolidine, low melting waxes and ion exchange resins.

Liquid carriers may be used in preparing solutions, suspensions,emulsions, syrups and elixirs. The active ingredient of this inventioncan be dissolved or suspended in a pharmaceutically acceptable liquidcarrier such as water, an organic solvent, a mixture of both orpharmaceutically acceptable oils or fat. The liquid carrier can containother suitable pharmaceutical additives such as solubilizers,emulsifiers, buffers, preservatives, sweeteners, flavoring agents,suspending agents, thickening agents, colors, viscosity regulators,stabilizers or osmo-regulators. Suitable examples of liquid carriers fororal and parenteral administration include water (particularlycontaining additives as above, e.g. cellulose derivatives, preferablysodium carboxymethyl cellulose solution), alcohols (including monohydricalcohols and polyhydric alcohols e.g. glycols) and their derivatives,and oils (e.g. fractionated coconut oil and arachis oil). For parenteraladministration the carrier can also be an oily ester such as ethyloleate and isopropyl myristate. Sterile liquid carriers are used insterile liquid form compositions for parenteral administration. Theliquid carrier for pressurized compositions can be halogenatedhydrocarbon or other pharmaceutically acceptable propellant.

Liquid pharmaceutical compositions which are sterile solutions orsuspensions can be administered by, for example, intramuscular,intraperitoneal or subcutaneous injection. Sterile solutions can also beadministered intravenously. Oral administration may be either liquid orsolid composition form.

The compounds of this invention may be administered rectally orvaginally in the form of a conventional suppository. For administrationby intranasal or intrabronchial inhalation or insulation, the compoundsof this invention may be formulated into an aqueous or partially aqueoussolution, which can then be utilized in the form of an aerosol. Thecompounds of this invention may also be administered transdermallythrough the use of a transdermal patch containing the active compoundand a carrier that is inert to the active compound, is non toxic to theskin, and allows delivery of the agent for systemic absorption into theblood stream via the skin. The carrier may take any number of forms suchas creams and ointments, pastes, gels, and occlusive devices. The creamsand ointments may be viscous liquid or semisolid emulsions of either theoil-in-water or water-in-oil type. Pastes comprised of absorptivepowders dispersed in petroleum or hydrophilic petroleum containing theactive ingredient may also be suitable. A variety of occlusive devicesmay be used to release the active ingredient into the blood stream suchas a semipermeable membrane covering a reservoir containing the activeingredient with or without a carrier, or a matrix containing the activeingredient. Other occlusive devices are known in the literature.

Preferably the pharmaceutical composition is in unit dosage form, e.g.as tablets, capsules, powders, solutions, suspensions, emulsions,granules, or suppositories. In such form, the composition is sub-dividedin unit dose containing appropriate quantities of the active ingredient;the unit dosage forms can be packaged compositions, for example packetedpowders, vials, ampoules, prefilled syringes or sachets containingliquids. The unit dosage form can be, for example, a capsule or tabletitself, or it can be the appropriate number of any such compositions inpackage form.

The dosage requirements vary with the particular compositions employed,the route of administration, the severity of the symptoms presented andthe particular subject being treated. Based on the results obtained inthe standard pharmacological test procedures, projected daily dosages ofactive compound would be 0.02 μg/kg-750 μg/kg. Treatment will generallybe initiated with small dosages less than the optimum dose of thecompound. Thereafter the dosage is increased until the optimum effectunder the circumstances is reached; precise dosages for oral,parenteral, nasal, or intrabronchial administration will be determinedby the administering physician based on experience with the individualsubject treated. Preferably, the pharmaceutical composition is in unitdosage form, e.g. as tablets or capsules. In such form, the compositionis sub-divided in unit dose containing appropriate quantities of theactive ingredient; the unit dosage forms can be packaged compositions,for example, packaged powders, vials, ampules, pre-filled syringes orsachets containing liquids. The unit dosage form can be, for example, acapsule or tablet itself, or it can be the appropriate number of anysuch compositions in package form.

The present invention includes prodrugs of compounds of Formula I.Prodrug, as used herein, means a compound which is convertible in vivoby metabolic means (e.g. by hydrolysis) to a compound of Formula I.Various forms of prodrugs are known in the art, for example, asdiscussed in Bundgaard, (ed.), Design of Prodrugs, Elsevier (1985);Widder, et al. (ed.), Methods in Enzymology, vol. 4, Academic Press(1985); Krogsgaard-Larsen, et al., (ed). “Design and Application ofProdrugs, Textbook of Drug Design and Development, Chapter 5, 113-191(1991), Bundgaard, et al., Journal of Drug Delivery Reviews,8:1-38(1992), Bundgaard, J. of Pharmaceutical Sciences, 77:285 et seq.(1988); and Higuchi and Stella (eds.) Prodrugs as Novel Drug DeliverySystems, American Chemical Society (1975).

EXAMPLES

The following provides the preparation of compounds representative ofthis invention.

Example 1 Cis and trans1,2,3,4,8,8a,9,10,11,11a-decahydro-cyclopenta[b][1,4]diazepino[6,7,1-ij]quinolineStep 1—2,3-dihydro-1H-cyclopenta[b]quinoline

Titanium tetrachloride (1.84 ml, 16.8 mmole) was added dropwise viasyringe to a stirred suspension of Zn powder (1.1 g, 16.8 mmole) infreshly distilled dry THF (20 ml) at room temperature under nitrogen.When the addition was complete, the mixture was stirred at roomtemperature for 1.5 hours. To the suspension of low-valent titaniumreagent formed, Anthranil (0.85 ml, 8.4 mmol) and1-pyrrolidino-1-cyclopentene (4.9 ml, 33.6 mmol) dissolved in dry THF(15 ml) were added carefully. After 15 minutes, 20% NaOH (9 ml) is addedwith stirring and the organic phase was decanted off and dried overMgSO₄ and concentrated. Purification by flash chromatography (40% ethylacetate/petroleum ether) gave the title compound as a brown oil, whichwas used directly in the next step.

Step 2—Cis and Trans 2,3,3a,4,9,9a-Hexahydro-1H-cyclopenta[b]quinoline

The title compound was prepared by catalytic hydrogenation of2,3-dihydro-1H-cyclopenta[b]quinoline (0.5 g, 2.43 mmol) in the presenceof PtO₂ and hydrogen (45 psi) in methanol (50 ml) to give the cis andtrans isomers. Separation by flash chromatography (10-30% ethylacetate/petroleum ether) gave the title compounds as light yellow solids(75%).

Cis 2,3,3a,4,9,9a-Hexahydro-1H-cyclopenta[b]quinoline

mp 60-65° C.; Anal. calc. for C₁₂H₁₅N: C, 83.19; H, 8.73; N, 8.08.Found: C, 83.2; H, 8.45; N, 8.02. MS m/e (ES+): 174 (M+H). ¹H NMR(DMSO-d₆) δ 6.85 (2H, m), 6.45 (1H, d, J=7.3 Hz), 6.40 (1H, t, J=7.2Hz), 5.5 (1H, s), 3.55 (1H, m), 2.75 (1H, dd, J=15.5, 5.8 Hz), 2.37 (1H,dd, J=15.5, 5.8 Hz), 2.12 (1H,m), 1.75 (3H, m), 1.54 (2H, m) 1.28 (1H,m).

Trans 2,3,3a,4,9,9a-Hexahydro-1H-cyclopenta[b]quinoline

mp 61° C.; Anal. calc. for C₁₂H₁₅N: C, 83.19; H, 8.73; N, 8.08. Found:C, 83.16; H, 8.44; N, 8. MS m/e (ES+): 174 (M+H). ¹H NMR (DMSO-d₆) δ6.86 (2H, m), 6.49 (2H, m), 5.86 (1H, s), 2.81 (2H, m), 2.56 (1H,m),1.93 (2H,m), 1.76 (2H,m), 1.62 (1H, m), 1.36 (1H, m) 1.20 (1H, m).

Step 3—Cis and Trans(1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-acetonitrile

To a stirred suspension of Cis2,3,3a,4,9,9a-Hexahydro-1H-cyclopenta[b]quinoline (0.41 g, 2.35 mmole),K₂CO₃ (1.6 g, 11.8 mmole) and tetrabutyl ammonium Iodide (0.87 g, 2.35mmole) in dry THF was added bromoacetonitrile (0.25 ml, 3.5 mmole). Thereaction mixture was heated to 70° C. for 12 hours, then cooled to roomtemperature and filtered. The reaction was diluted with ethyl acetateand washed with water (25 mL) and brine (25 mL). The organic layer wasdried with MgSO₄. Evaporation and flash chromatography (10% ethylacetate/petroleum ether) gave 405 mg (81% yield) of the product as agray brown solid. The same step 3 procedure was used to prepare thetrans isomer except that trans2,3,3a,4,9,9a-Hexahydro-1H-cyclopenta[b]quinoline was used instead ofthe cis isomer.

Cis (1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-acetonitrile

mp 70-71° C. Anal. calc. for C₁₄H₁₆N₂: C, 79.21; H, 7.6; N, 13.2. Found:C, 78.97; H, 7.61; N, 13.17. MS m/e (ES+): 213 (M+H). ¹H NMR (DMSO-d₆) δ7.14 (1H, t, J=7.5 Hz), 7.05 (1H, d, J=7.2 Hz), 6.79 (1H, d, J=8.0 Hz),6.74 (1H, t, J=7.3 Hz), 4.46 (2H, ABq, J=18 Hz, Δδ=0.13), 3.47 (1H, q,J=8.0 Hz), 2.65 (1H, dd, J=14, 5.2 Hz), 2.31 (1H, m), 2.23 (1H, m), 2.15(1H, m), 1.94 (1H, m), 1.69 (1H, m) 1.44 (3H, m).

Trans (1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-acetonitrile

Light gray solid (99%), mp 80-81° C.; Anal. calc. for C₁₄H₁₆N₂: C,79.21; H, 7.6; N, 13.2. Found: C, 78.64H, 7.37; N, 13.1. MS m/e (ES+):213 (M+H). ¹H NMR (DMSO-d₆) δ 7.11 (1H, t, J=7.5 Hz), 7.03 (1H, d, J=7.5Hz), 6.95 (1H, d, J=8.2 Hz), 6.77 (1H, t, J=7.3 Hz), 4.80 (1H, d, J=18.5Hz), 4.16 (1H, d, J=18.5 Hz), 2.86 (1H, dd, J=15.9, 4.9 Hz), 2.79 (1H,m), 2.63 (1H, m) 2.17 (1H, m), 1.99 (1H, m), 1.82 (3H, m), 1.39 (2H, m).

Step 4—Cis and trans2-(1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-ethylamine

Catalytic hydrogenation of Cis(1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-acetonitrile (0.23g, 1.08 mmol) in the presence of 5% Rh on Alumina and hydrogen (45 psi)in a 1:1 mixture of ethanol:ammonium hydroxide (40 ml) afforded thetitle compound. The reaction mixture was filtered through celiteconcentrated in vacuo and purified by flash chromatography (10% 2N NH₃in ethanol/dichloromethane) and converted to the HCl salt to give awhite solid. The same step 4 procedure was used to prepare the transisomer except that Trans(1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-acetonitrile wasused instead of the cis isomer.

Cis 2-(1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-ethylamine

(0.27 mg, 98%): mp 215-220° C.; Anal. calc. for C₁₄H₂₀N₂—HCl-0.25H₂O: C,65.36; H, 8.42; N, 10.88. Found: C, 65.35; H, 8.21; N, 10.63. MS m/e(ES+): 217 (M+H). ¹H NMR (DMSO-d₆) δ 7.92 (3H, bs), 7.05 (1H, t, J=8.5Hz), 6.99 (1H, d, J=7.0 Hz), 6.71 (1H, d, J=8.1 Hz), 6.61 (1H, t, J=7.3Hz), 3.50 (3H, m), 2.95 (2H, m), 2.62 (1H, dd, J=15, 5.0 Hz), 2.30 (2H,m), 2.02 (1H, m), 1.85 (1H, m), 1.60 (1H, m) 1.35 (3H, m).

Trans 2-(1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-ethylamine

Off white solid (97%), mp 225-230° C.; Anal. calc. forC₁₄H₂₀N₂—HCl-0.75H₂O: C, 63.15; H, 8.45; N, 10.52. Found: C, 63.53H,8.11; N, 10.41. MS m/e (ES+): 217 (M+H). ¹H NMR (DMSO-d₆) δ 7.93 (3H,bs), 7.03 (1H, t, J=7.5 Hz), 6.94 (1H, d, J=7.2 Hz), 6.78 (1H, d, J=8.2Hz), 6.61 (1H, t, J=7.3 Hz), 3.65 (1H, m), 2.93 (2H, m), 2.80 (2H, m),2.59 (1H, m), 2.07 (1H, m) 1.78 (4H, m), 1.45 (1H, m), 1.27 (2H, m).

Step 5—Cis and Trans1,2,3,4,8,8a,9,10,11,11a-decahydro-cyclopenta[b][1,4]diazepino[6,7,1-ij]quinoline

A flask containing Cis2-(1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-ethylamine (0.18g, 0.84 mmol) and 0.07 ml of 37% aqueous formaldehyde in 2 ml of EtOHwas treated with TFA (0.07 mL, 0.92 mmol) at room temperature for 1 hr.The mixture was concentrated under reduced pressure, and the residue wastaken up in dichloromethane, washed with 1 N NaOH (15 mL), Brine (15 mL)and then dried with MgSO₄. Evaporation and flash chromatography (10% 2NNH₃ in ethanol/dichloromethane) afforded the title compound, which wasconverted to the HCl salt to give a brown solid (0.19 mg, 85%): The samestep 5 procedure was used to prepare the trans isomer except that Trans2-(1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-ethylamine wasused instead of the cis isomer.

Cis1,2,3,4,8,8a,9,10,11,11a-decahydro-cyclopenta[b][1,4]diazepino[6,7,1-ij]quinoline

mp 180-190° C. (Decomposed); Anal. calc. for C₁₅H₂₀N₂—HCl-0.75H₂O: C,64.74; H, 8.15; N, 10.06. Found: C, 64.64; H, 8.18; N, 9.66. MS m/e(ES+): 229 (M+H). ¹H NMR (DMSO-d₆) δ 9.23 (2H, bs), 7.01 (2H, t, J=8.1Hz), 6.66 (1H, t, J=7.3 Hz), 4.20 (2H, ABq, J=14 Hz, Δδ=0.04), 3.78 (1H,m), 3.60 (1H, m), 3.40 (2H, m), 3.24 (1H, m), 2.67 (1H, m), 2.38 (2H,m), 1.91 (1H, m), 1.76 (1H, m), 1.54 (3H, m), 1.21 (1H, m).

Trans-1,2,3,4,8,8a,9,10,11,11a-decahydro-cyclopenta[b][1,4]diazapino[6,7,1-ij]quinoline

Light green solid (72%), mp 190° C. (Decomposed); Anal. calc. forC₁₅H₂₀N₂—HCl-0.5H₂O: C, 65.80; H, 8.10; N, 10.23. Found: C, 65.50; H,8.2; N, 9.78. MS m/e (ES+): 229 (M+H). ¹H NMR (DMSO-d₆) δ 9.12 (2H, bs),7.12 (1H, d, J=7.3 Hz), 7.03 (1H, d, J=7.3 Hz), 6.77 (1H, t, J=7.3 Hz),4.32 (1H, d, J=14 Hz), 3.87 (1H, d, J=14 Hz), 3.41 (2H, m), 3.08 (2H,m), 2.81 (2H, m), 2.64 (1H, m), 2.11 (1H, m), 1.91 (1H, m), 1.77 (3H,m), 1.45 (1H, m), 1.29 (1H, m).

Example 2 Step 1—2,3-dihydro-1H-cyclohexa[b]quinoline

The title compound was prepared according to the procedure of Example 1step 1 except that 1-pyrrolidino-1-cyclohexene was used as thedienophile to give a light brown oil (84%) and was used directly in thenext step.

Step 2—Cis and Trans-1,2,3,4,4a,9,9a,10-octahydroacridine

The title compounds were prepared according to the procedure of Example1 step 2, except that 2,3-dihydro-1H-cyclohexa[b]quinoline washydrogenated instead of 2,3-dihydro-1H-cyclopenta[b]quinoline.Separation by flash chromatography (10-30% ethyl acetate/petroleumether) gave the cis/trans isomers as white solids (74%).

Cis-1,2,3,4,4a,9,9a,10-octahydroacridine

mp 69-70° C.; Anal. calc. for C₁₃H₁₇N: C, 83.37; H, 9.15; N, 7.48.Found: C, 83.06; H, 9.1; N, 7.43. MS m/e (ES+): 188 (M+H). ¹H NMR(DMSO-d₆) δ 6.81 (2H, m), 6.43 (1H, d, J=7.5 Hz), 6.36 (1H, t, J=7.3Hz), 5.44 (1H, s), 3.38 (1H, d, J=3.2 Hz), 2.79 (1H, dd, J=16.2, 5.5Hz), 2.41 (1H, dd, J=16.2, 4 Hz), 1.85 (1H, t, J=3.8 Hz), 1.69 (1H, m),1.53 (3H, m), 1.32 (4H, m).

Trans-1,2,3,4,4a,9,9a,10-octahydroacridine

mp 78-79° C.; Anal. calc. for C₁₃H₁₇N: C, 83.37; H, 9.15; N, 7.48.Found: C, 82.94; H, 9.2; N, 7.31. MS m/e (ES+): 188 (M+H). ¹H NMR(DMSO-d₆) δ 6.82 (2H, m), 6.41 (2H, m), 5.50 (1H, s), 2.75 (1H, m), 2.51(1H, dd, J=16.0, 4.7 Hz), 2.37 (1H, dd, J=16.0, 12 Hz), 1.90 (1H, m),1.81 (1H, d, J=6.3 Hz), 1.71 (2H, t, J=11.3 Hz), 1.31 (3H, m), 1.17 (1H,m), 0.95 (1H, m).

Step 3—Cis andTrans-2,3,4,4a,9,9a,-hexahydroacridin-10(1H)-ylacetonitrile

The title compounds were prepared according to the procedure of Example1 step 3 except that Cis and Trans-1,2,3,4,4a,9,9a,10-octahydroacridinewere used instead of Cis and Trans2,3,3a,4,9,9a-Hexahydro-1H-cyclopenta[b]quinoline, respectively.

Cis-2,3,4,4a,9,9a,-hexahydroacridin-10(1H)-ylacetonitrile

Light green solid (86%): mp 86° C.; Anal. calc. for C₁₅H₁₈N₂: C, 79.61;H, 8.02; N, 12.38. Found: C, 79.29; H, 8.08; N, 12.4. MS m/e (ES+): 227(M+H). ¹H NMR (DMSO-d₆) δ 7.06 (1H, t, J=7.2 Hz), 6.98 (1H, d, J=7.3Hz), 6.65 (2H, m), 4.48 (2H, ABq, J=16.2 Hz, Δδ=0.05), 3.34 (1H, m),2.89 (1H, dd, J=16.2, 6.3 Hz), 2.49 (1H, m), 2.14 (1H,m), 1.81 (1H, m),1.63 (3H, m), 1.44 (3H, m) 1.29 (1H, m).

Trans-2,3,4,4a,9,9a,-hexahydroacridin-10(1H)-ylacetonitrile

Light yellow solid (97%) mp 86° C.; Anal. calc. for C₁₅H₁₈N₂: C, 79.61;H, 8.02; N, 12.38. Found: C, 78.95; H, 8.19; N, 12.18. MS m/e (ES+): 227(M+H). ¹H NMR (DMSO-d₆) δ 7.03 (1H, t, J=7.3 Hz), 6.90 (1H, d, J=7.3Hz), 6.81 (1H, d, J=7.7 Hz), 6.65 (1H, t, J=7.3 Hz), 4.45 (2H, ABq,J=18.7 Hz, Δδ=0.32), 2.67 (1H, m), 2.54 (1H, dd, J=16, 4.2 Hz), 2.40(1H, dd, J=5.8, 2.3 Hz), 2.26 (1H, m), 1.79 (2H, m), 1.63 (1H, m), 1.49(1H, m) 1.27 (2H, m), 1.07 (2H, m).

Step 4—2-[(Cis) and(Trans)-2,3,4,4a,9,9a,-hexahydroacridin-10(1H)-yl]ethylamine

The title compound was prepared according to the procedure of Example 1step 4, except that Cis andTrans-2,3,4,4a,9,9a,-hexahydroacridin-10(1H)-ylacetonitrile were usedinstead of Cis and Trans(1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-acetonitrile,respectively.

2-[(Cis)-2,3,4,4a,9,9a,-hexahydroacridin-10(1H)-yl]ethylamine

Off white solid (96%): mp 205-210° C. Anal. calc. forC₁₅H₂₂N₂—HCl-0.25H₂O: C, 66.41; H, 8.73; N, 10.32. Found: C, 65.25; H,8.33; N, 10.11. MS m/e (ES+): 231 (M+H). ¹H NMR (DMSO-d₆) δ 7.94 (3H,bs), 6.98 (1H, t, J=7.2 Hz), 6.92 (1H, d, J=7.3 Hz), 6.61 (1H, d, J=8.2Hz), 6.51 (1H, t, J=7.3 Hz), 3.56 (1H, m), 3.42 (1′H, m), 3.22 (1H, m),2.92 (3H,m), 2.42 (1H, dd, J=16.2, 5.0 Hz), 2.20 (1H, m), 1.56 (4H, m)1.34 (2H, m), 1.26 (2H, m).

2-[(Trans)-2,3,4,4a,9,9a,-hexahydroacridin-10(1H)-yl]ethylamine

Off white solid (85%) mp 102° C. Anal. calc. for C₁₅H₂₂N₂: C, 78.21; H,9.63; N, 12.16. Found: C, 78.1; H, 9.63; N, 12.07. MS m/e (ES+): 231(M+H). ¹H NMR (DMSO-d₆) δ 6.90 (1H, t, J=8.3 Hz), 6.76 (1H, d, J=7.2Hz), 6.60 (1H, d, J=8.2 Hz), 6.42 (1H, t, J=7.2 Hz), 3.27 (3H, m), 3.05(1H, m), 2.69 (2H, m), 2.51 (1H, m), 2.32 (2H, m) 1.76 (1H,m), 1.62 (1H,m), 1.40 (2H, m), 1.27 (2H, m), 1.02 (2H, m).

Step 5—(Cis) and(Trans)-1,2,3,4,8a,9,10,11,12,12a,-decahydro-8H-[1,4]diazepino[6,7,1-de]acridine

The title compound was prepared according to the procedure of Example 1step 5, except that 2-[(Cis) and(Trans)-2,3,4,4a,9,9a,-hexahydroacridin-10(1H)-yl]ethylamine were usedinstead of Cis and Trans2-(1,2,3,3a,9,9a-Hexahydro-cyclopenta[b]quinolin-4-yl)-ethylamine,respectively.

(Cis)-1,2,3,4,8a,9,10,11,12,12a,-decahydro-8H-[1,4]diazepino[6,7,1-de]acridine

Light green solid (77%): mp 150-155° C. Anal. calc. forC₁₆H₂₂N₂—HCl-0.75H₂O: C, 65.74; H, 8.45; N, 9.58. Found: C, 65.74; H,8.24; N, 9.22. MS m/e (ES+): 243 (M+H). ¹H NMR (DMSO-d₆) δ 9.32 (1H,bs), 8.70 (1H, bs), 7.08 (1H, d, J=7.4 Hz), 6.80 (1H, d, J=6.8 Hz), 6.73(1H, t, J=7.3 Hz), 4.20 (1H, d, J=12.1 Hz), 3.86 (1H, dd, J=13.5, 9.8Hz), 3.44 (1H, m), 3.17 (1H, m), 3.01 (2H, d, J=10.9 Hz), 2.73 (1H, dd,J=16.4, 5.4 Hz), 2.53 (1H, dd, J=16.4, 7.0 Hz), 2.08 (1H, m), 1.37 (9H,m).

(Trans)-1,2,3,4,8a,9,10,11,12,12a,-decahydro-8H-[1,4]diazepino[6,7,1-de]acridine

Light tan solid (69%) mp 95° C. Anal. calc. for C₁₆H₂₂N₂: C, 79.29; H,9.15; N, 11.56. Found: C, 78.53; H, 9.15; N, 11.32. MS m/e (ES+): 243(M+H). ¹H NMR (DMSO-d₆) δ 6.84 (1H, d, J=7.3 Hz), 6.74 (1H, d, J=7.3Hz), 6.54 (1H, t, J=7.3 Hz), 3.75 (1H, d, J=14 Hz), 3.36 (1H, d, J=14Hz), 3.19 (1H, d, J=14 Hz), 2.94 (1H, d, J=12 Hz), 2.58 (4H, m), 2.38(2H, m), 2.01 (1H, m), 1.79 (1H, d, J=12 Hz), 1.65 (2H, m), 1.24 (3H,m), 1.05 (2H, m).

1. A compound of Formula I

wherein: R¹ is hydrogen or alkyl of 1 to 6 carbon atoms; R² and R³ areeach, independently, hydrogen, hydroxy, alkyl of 1-6 carbon atoms,alkoxy of 1-6 carbon atoms, halogen, carboxamido, carboalkoxy of two tosix carbon atoms, perfluoroalkyl of 1-6 carbon atoms, cyano,alkanesulfonamido of 1-6 carbon atoms, alkanesulfonyl of 1-6 carbonatoms, alkanamido of 1-6 carbon atoms, amino, alkylamino of 1-6 carbonatoms, dialkylamino of 1-6 carbon atoms per alkyl moiety,perfluoroalkoxy of 1-6 carbon atoms, alkanoyloxy of 2 to 6 carbon atoms,alkanoyl of 2 to 6 carbon atoms, aroyl of 6 to 8 carbon atoms, aryl of 5to 7 carbon atoms, a C₆ to C₁₃ alkylaryl group having 5 to 7 carbonatoms in the aryl moiety, a 5 to 7 membered heteroaryl group, or a 6 to13 membered alkylheteroaryl group having 5 to 7 members in theheteroaryl moiety, wherein any R² or R³ substituent having an aryl orheteroaryl moiety may optionally be substituted on the aryl orheteroaryl moiety with 1 to 3 substituents independently selected from ahalogen atom, a C₁-C₆ alkyl group, or a C₁-C₆ alkoxy group; R⁴ and R⁵are, independently, hydrogen or alkyl of 1 to 6 carbon atoms, or R⁴ andR⁵, taken together with the carbons to which they are attached, form acyclic moiety selected from a cycloalkane of 4 to 8 carbon atoms,cycloalkene of 4 to 8 carbon atoms, bridged bicyclic alkane of 5 to 10carbon atoms, bridged bicyclic alkene of 5 to 10 carbon atoms, pyran orthiopyran in which the sulfur atom is optionally oxidized to thesulfoxide or sulfone, wherein the cyclic moiety formed by R⁴ and R⁵ mayoptionally be substituted with 1 to 3 substituents independentlyselected from a halogen atom, a C₁-C₆ alkyl group, or a C₁-C₆ alkoxygroup; R⁶ and R⁷ are each, independently, hydrogen or alkyl of 1 to 6carbon atoms; and n is 1 or 2, with the proviso that when n is 1, R⁴ andR⁵ are, independently hydrogen or alkyl of 1 to 6 carbon atoms; or apharmaceutically acceptable salt thereof.
 2. The compound of claim 1wherein, R² and R³ independently, are hydrogen, halogen, cyano,perfluoroalkyl of 1 to 3 carbon atoms, phenyl or alkoxy of 1 to 3 carbonatoms.
 3. The compound of claim 1 wherein R⁴ and R⁵ are taken together,along with the carbon atoms to which they are attached, to form acycloalkane or cycloalkene moiety of 5 to 8 carbon atoms, where one ormore of the carbon atoms are optionally substituted by alkyl of 1 to 4carbon atoms.
 4. The compound of claim 1 wherein R⁴ and R⁵ are takentogether, along with the carbon atoms to which they are attached, toform a cycloalkane moiety of 5 to 7 carbon atoms.
 5. The compound ofclaim 1 wherein n is
 1. 6. The compound of claim 1 wherein R¹, R⁶ and R⁷are hydrogen.
 7. The compound of claim 1 wherein R² and R³ areindependently selected from hydrogen, halo, trifluoromethyl, phenyl oralkoxy of 1 to 3 carbon atoms; R¹, R⁶ and R⁷ are each hydrogen; n is 2;and R⁴ and R⁵, taken together with the carbon atoms to which they areattached, form cyclopentane, cyclohexane or cycloheptane.
 8. Thecompound of claim 1 wherein R⁴ and R⁵ are independently hydrogen oralkyl of 1 to 6 carbon atoms.
 9. The compound of claim 1 wherein R⁴ andR⁵ are independently, hydrogen or alkyl of 1 to 6 carbon atoms and nis
 1. 10. A method of treating a mammal suffering from a conditionselected from epilepsy, sleep disorders, migraines, sexual dysfunction,gastrointestinal disorders, or obesity comprising providing to themammal suffering from the condition, a therapeutically effective amountof at least one compound of claim 1 or a pharmaceutically acceptablesalt thereof.
 11. The method of claim 10 wherein the condition isobesity.
 12. The method of claim 10 wherein the mammal is a human.
 13. Amethod of treating a mammal suffering from a central nervous systemdeficiency associated with trauma, stroke, or spinal cord injurycomprising providing to the mammal suffering from the condition, atherapeutically effective amount of at least one compound of claim 1 ora pharmaceutically acceptable salt thereof.
 14. The method of claim 13wherein the mammal is a human.
 15. A method of treating a mammalsuffering from a condition selected from schizophrenia, schizophreniformdisorder, schizoaffective disorder, delusional disorder,substance-induced psychotic disorder, L-DOPA-induced psychosis,psychosis associated with Alzheimer's dementia, psychosis associatedwith Parkinson's disease, psychosis associated with Lewy body disease,dementia, memory deficit, or intellectual deficit disorder associatedwith Alzheimer's disease comprising providing to the mammal sufferingfrom the condition, a therapeutically effective amount of at least onecompound of Formula I

wherein: R¹ is hydrogen or alkyl of 1 to 6 carbon atoms; R² and R³ areeach, independently, hydrogen, hydroxy, alkyl of 1-6 carbon atoms,alkoxy of 1-6 carbon atoms, halogen, carboxamido, carboalkoxy of two tosix carbon atoms, perfluoroalkyl of 1-6 carbon atoms, cyano,alkanesulfonamido of 1-6 carbon atoms, alkanesulfonyl of 1-6 carbonatoms, alkanamido of 1-6 carbon atoms, amino, alkylamino of 1-6 carbonatoms, dialkylamino of 1-6 carbon atoms per alkyl moiety,perfluoroalkoxy of 1-6 carbon atoms, alkanoyloxy of 2 to 6 carbon atoms,alkanoyl of 2 to 6 carbon atoms, aroyl of 6 to 8 carbon atoms, aryl of 5to 7 carbon atoms, a C₆ to C₁₃ alkylaryl group having 5 to 7 carbonatoms in the aryl moiety, a 5 to 7 membered heteroaryl group, or a 6 to13 membered alkylheteroaryl group having 5 to 7 members in theheteroaryl moiety, wherein any R² or R³ substituent having an aryl orheteroaryl moiety may optionally be substituted on the aryl orheteroaryl moiety with 1 to 3 substituents independently selected from ahalogen atom, a C₁-C₆ alkyl group, or a C₁-C₆ alkoxy group; R⁴ and R⁵are, independently, hydrogen or alkyl of 1 to 6 carbon atoms, or R⁴ andR⁵, taken together with the carbons to which they are attached, form acyclic moiety selected from a cycloalkane of 4 to 8 carbon atoms,cycloalkene of 4 to 8 carbon atoms, bridged bicyclic alkane of 5 to 10carbon atoms, bridged bicyclic alkene of 5 to 10 carbon atoms, pyran orthiopyran in which the sulfur atom is optionally oxidized to thesulfoxide or sulfone, wherein the cyclic moiety formed by R⁴ and R⁵ mayoptionally be substituted with 1 to 3 substituents independentlyselected from a halogen atom, a C₁-C₆ alkyl group, or a C₁-C₆ alkoxygroup; R⁶ and R⁷ are each, independently, hydrogen or alkyl of 1 to 6carbon atoms; and n is 1 or 2, with the proviso that when n is 1, R⁴ andR⁵ are, independently hydrogen or alkyl of 1 to 6 carbon atoms; or apharmaceutically acceptable salt thereof.
 16. The method of claim 15wherein the condition is schizophrenia.
 17. The method of claim 15wherein the mammal is human.
 18. A method of treating a mammal sufferingfrom a condition selected from bipolar disorders, depressive disorders,mood episodes, anxiety disorders, adjustment disorders, or eatingdisorders comprising providing to the mammal suffering from thecondition, a therapeutically effective amount of at least one compoundof Formula I

wherein: R¹ is hydrogen or alkyl of 1 to 6 carbon atoms; R² and R³ areeach, independently, hydrogen, hydroxy, alkyl of 1-6 carbon atoms,alkoxy of 1-6 carbon atoms, halogen, carboxamido, carboalkoxy of two tosix carbon atoms, perfluoroalkyl of 1-6 carbon atoms, cyano,alkanesulfonamido of 1-6 carbon atoms, alkanesulfonyl of 1-6 carbonatoms, alkanamido of 1-6 carbon atoms, amino, alkylamino of 1-6 carbonatoms, dialkylamino of 1-6 carbon atoms per alkyl moiety,perfluoroalkoxy of 1-6 carbon atoms, alkanoyloxy of 2 to 6 carbon atoms,alkanoyl of 2 to 6 carbon atoms, aroyl of 6 to 8 carbon atoms, aryl of 5to 7 carbon atoms, a C₆ to C₁₃ alkylaryl group having 5 to 7 carbonatoms in the aryl moiety, a 5 to 7 membered heteroaryl group, or a 6 to13 membered alkylheteroaryl group having 5 to 7 members in theheteroaryl moiety, wherein any R² or R³ substituent having an aryl orheteroaryl moiety may optionally be substituted on the aryl orheteroaryl moiety with 1 to 3 substituents independently selected from ahalogen atom, a C₁-C₆ alkyl group, or a C₁-C₆ alkoxy group; R⁴ and R⁵are, independently, hydrogen or alkyl of 1 to 6 carbon atoms, or R⁴ andR⁵, taken together with the carbons to which they are attached, form acyclic moiety selected from a cycloalkane of 4 to 8 carbon atoms,cycloalkene of 4 to 8 carbon atoms, bridged bicyclic alkane of 5 to 10carbon atoms, bridged bicyclic alkene of 5 to 10 carbon atoms, pyran orthiopyran in which the sulfur atom is optionally oxidized to thesulfoxide or sulfone, wherein the cyclic moiety formed by R⁴ and R⁵ mayoptionally be substituted with 1 to 3 substituents independentlyselected from a halogen atom, a C₁-C₆ alkyl group, or a C₁-C₆ alkoxygroup; R⁶ and R⁷ are each, independently, hydrogen or alkyl of 1 to 6carbon atoms; and n is 1 or 2, with the proviso that when n is 1, R⁴ andR⁵ are, independently hydrogen or alkyl of 1 to 6 carbon atoms; or apharmaceutically acceptable salt thereof.
 19. The method of claim 18wherein the bipolar disorder is bipolar I disorder, bipolar II disorder,or cyclothymic disorder; the depressive disorder is major depressivedisorder, dysthymic disorder, or substance-induced mood disorder; themood episode is major depressive episode, manic episode, mixed episode,or hypomanic episode; the anxiety disorder is panic attack, agoraphobia,panic disorder, specific phobia, social phobia, obsessive compulsivedisorder, posttraumatic stress disorder, acute stress disorder,generalized anxiety disorder, separation anxiety disorder, orsubstance-induced anxiety disorder.
 20. The method of claim 18 whereinthe condition is depressive disorder, bipolar disorder or mood episode.21. The method of claim 18 wherein the mammal is human.
 22. Apharmaceutical composition comprising a) at least one compound ofFormula I

wherein: R¹ is hydrogen or alkyl of 1 to 6 carbon atoms; R² and R³ areeach, independently, hydrogen, hydroxy, alkyl of 1-6 carbon atoms,alkoxy of 1-6 carbon atoms, halogen, carboxamido, carboalkoxy of two tosix carbon atoms, perfluoroalkyl of 1-6 carbon atoms, cyano,alkanesulfonamido of 1-6 carbon atoms, alkanesulfonyl of 1-6 carbonatoms, alkanamido of 1-6 carbon atoms, amino, alkylamino of 1-6 carbonatoms, dialkylamino of 1-6 carbon atoms per alkyl moiety,perfluoroalkoxy of 1-6 carbon atoms, alkanoyloxy of 2 to 6 carbon atoms,alkanoyl of 2 to 6 carbon atoms, aroyl of 6 to 8 carbon atoms, aryl of 5to 7 carbon atoms, a C₆ to C₁₃ alkylaryl group having 5 to 7 carbonatoms in the aryl moiety, a 5 to 7 membered heteroaryl group, or a 6 to13 membered alkylheteroaryl group having 5 to 7 members in theheteroaryl moiety, wherein any R² or R³ substituent having an aryl orheteroaryl moiety may optionally be substituted on the aryl orheteroaryl moiety with 1 to 3 substituents independently selected from ahalogen atom, a C₁-C₆ alkyl group, or a C₁-C₆ alkoxy group; R⁴ and R⁵are, independently, hydrogen or alkyl of 1 to 6 carbon atoms, or R⁴ andR⁵, taken together with the carbons to which they are attached, form acyclic moiety selected from a cycloalkane of 4 to 8 carbon atoms,cycloalkene of 4 to 8 carbon atoms, bridged bicyclic alkane of 5 to 10carbon atoms, bridged bicyclic alkene of 5 to 10 carbon atoms, pyran orthiopyran in which the sulfur atom is optionally oxidized to thesulfoxide or sulfone, wherein the cyclic moiety formed by R⁴ and R⁵ mayoptionally be substituted with 1 to 3 substituents independentlyselected from a halogen atom, a C₁-C₆ alkyl group, or a C₁-C₆ alkoxygroup; R⁶ and R⁷ are each, independently, hydrogen or alkyl of 1 to 6carbon atoms; and n is 1 or 2, with the proviso that when n is 1, R⁴ andR⁵ are, independently hydrogen or alkyl of 1 to 6 carbon atoms; or apharmaceutically acceptable salt thereof; and b) at least onepharmaceutically acceptable carrier or excipient.